The immigration minister, Mark Harper resigned after his cleaner was found to not legally be permitted to be in the UK. Photograph: Adrian Sherratt/Rex Features

As the shockwaves from Mark Harper giving up his ministerial position to spend more time with his ironing ripple through Westminster, I imagine a number of MPs are reviewing their domestic arrangements. Maintenance of decorative duck islands will be suspended until further notice. Moats will be left to overflow, half-dredged. Flowering clematises will be abandoned to the elements. The Harper affair may be funny, but it also reveals the absurdity at the centre of this government's immigration policies.

For seven years, Harper employed a Colombian woman named Isabella Acevedo to clean for him. He claimed £22 for four hours per week on his expenses, although reportedly he may have paid her a bit more. He did nothing illegal, claimed the home secretary, Theresa May, because Acevedo was self-employed. Harper clings to the mantle of innocence and dignity while the woman who scrubbed his toilet for seven years, for the minimum wage, faces arrest and deportation.

The immigration bill is meandering its way through the legislative process, essentially unopposed. It doubles fines for those who employ undocumented workers and requires landlords and doctors to perform immigration checks. But if the minister for immigration can be fooled for seven years, what hope have they? Few people, when presented with an official-looking document, have time to telephone the Home Office and investigate its veracity. A proposed "response line", promising a turnaround within 48 hours, is manifestly ludicrous.

Millions of new leases are agreed every year. Millions of new employment contracts are signed. Six hundred thousand new patient registrations take place annually within the auspices of the NHS. Funding a department that could cope with such demand is not realistic; the cost to benefit ratio is prohibitive. The net result will be pure discrimination. Landlords, hospital receptionists and employers are essentially being asked to racially profile; to decide whether one looks "indigenous" enough, in their subjective judgment.

My good friend, let's call her Mona, is from Basildon. She has lived in Greece for almost 20 years – most of her adult life – and never paid tax in the UK. She has been registered with the GP practice close to her parents' home since before she left. She combines a yearly visit to her folks with general check-ups, scans and, on three occasions, giving birth to her lovely children. She enjoys this on top of being entitled (quite rightly) to health services back in Greece. Do you think Mona will ever be challenged over her eligibility? No. She doesn't have olive skin and an accent, like I do.

This is what is at the heart of this immigration policy. People who look or sound foreign will be picked on. They will be shunted on to self-employed status to protect their employer. Ministers will commission vans telling them to "go home", while enjoying their cheap labour. Brown tenants will lose out over white ones. Black markets will spring up for the documented to rent properties and then sublet them at a premium to the undocumented. Medical treatment will be refused. "What we've seen are many more migrants being turned away from doctor's surgeries and GPs", says Leigh Daynes, director of Doctors of the World UK, "even though the law hasn't yet changed."

Meanwhile, the EU commissioner for employment accuses David Cameron of posturing based on "myth", the Swiss have voted for plans to introduce immigration quotas and Greece has approved legislation to strip the right to vote from both migrants legally in Greece and Greeks who live abroad, rendering people like me stateless, while Athens ponders the possibility of its first fascist mayor. It is a dangerous time to look foreign, it seems, anywhere in Europe. The immigration debate is turning increasingly poisonous, for political gain. Acevedo is merely the latest victim.